Consumption is around 9.5~9.5mA during awake/normal periods and 0.2~0.3mA when in standby mode.

To make these measurements, I used a USB-serial adaptor to supply 5V to the NANO-ARM via the 5V pin and to receive serial data from D1 pin (=Serial1). This allowed me to insert my DMM in the 5V line to measure the current. (No other components involved.)

Both these two boards are double the price of the NANO-ARM. Looking at the schematics for all three boards, I can't see much to explain why the NANO-ARM is drawing so much more current than those other boards claim (I don't have either to do a side-by-side comparison). The NANO-ARM's circuit is pretty basic with few/no other components to consume much current. Even the regulators seem to be on a par.

I am wondering if there could be anything different in the Arduino Cores for the 3 boards that could explain the difference. The NANO-ARM and the Rocketscream use the Zero's Board definition which gives maximum compatibility with Arduino Zero. The board requires different or extra board definition.

Any help or guidance on reducing the standby current, or anyone else's experiences along these lines would be great.